# A simple thin-film transmittance calculation problem

I am trying to reproduce results of thin-film transmittance given in this article by using this online thin-film calculator tool (www.filmetrics.com). I would like to use the calculator later for more complex thin-film stacks so I just wanted to have a check with some reference. However, when I set the parameters like in the paper:

Stack

1.) Medium Air

2.) Au film 1 [nm] thick

3.) Substrate SiO2

the plot from the thin-film calculator does not match the results presented in the paper, what am I doing wrong ?

Thin-film calculator result

Thin-film article results

• The major difference that comes to mind is that the calculator assume a homogeneous film with given properties while, at least at nanometer scale the film is most likely grid like, you can have thickness fluctuations and even islands of materials separated by voids. Indeed increase in thickn. seems to increase the correspondence – Alchimista Jan 23 '19 at 9:21
• Thanks on the hint, yes it seems that increasing thickness gives more plausible results. Do you know where could I look up the data on some thicker films, I would like to check this web calculator against some reference? – miquo Jan 23 '19 at 16:27
• There are sure many. Try optical properties of thin film of metal for instance or ITO on glass and Google for images. ... – Alchimista Jan 23 '19 at 17:10
• Now I've followed your link and, you see, they refer to islands. ... – Alchimista Jan 23 '19 at 17:12
• You are right,I did not read the text carefully,I see now, thin film was used to produce the islands. Another thing, I have also tried the calculator with the following stack: 1.Medium Air 2. Acrylic 1mm thick 3.Substrate Air. This also did not give expected results, like absorption in UV and IR region, but gave flat transmittance ~0.92 from 200-2000nm and 0 absorptance. I suppose that this is because transmittance/reflectance are based on Fresnel equations and it does for account for interaction of photons with polymer molecules,only complex refractive index will produce absorptance, right ? – miquo Jan 23 '19 at 19:30